Did you know Porto was voted Best European Destination 2017?
Here is a small video with the reason why:
Porto has only one airport - Francisco Sá Carneiro Airport, (IATA: OPO).
There are a number of low cost companies that fly to Porto, like Ryanair, Easyjet, Wizzair, which provide many choices to get here. The airport is located 15km away from the city center, so you can easily reach the city center by taxi (>20min, about 20€), or metro (about 35min, cost about 2€+0,50€ for rechargeable ticket type Z4).
If you are visiting Portugal, train is a fairly cheap option to travel around most of the coastal areas. Tickets can be bought here: www.cp.pt